What are the parts of the plant, and how do they work?



Plant Classification (5 Kingdoms)






 Roots
 Stems
 Leaves
 Flowers
Major Plant Parts

Roots
 Functions:
 Absorb water and nutrients
 Anchor the plant, and support the above ground part of the plant.
 Store food.

Roots
 Root Systems:
 Fibrous: A system that has no dominant primary root.
 Tap: A system composed of one primary root and many secondary roots that branch off.

Fibrous

Tap Roots

Roots
 Primary Root: The first root to emerge at germination. May become the main tap root.
 Secondary Roots: Roots that branch out from the primary root.
 Apical Meristem: Area at the tip of the root where new cells develop

Roots
 Healthy Roots: Roots are white or nearly white, and smell fresh.
 Unhealthy Roots: Roots are black, brown, or dark orange and smell rotten and sour.

Stems
 Functions:
 Support the leaves, and positions them so they can receive as much sunlight as possible
 Responsible for the size and shape of the plant.

Stems
 Functions:
 Move water, minerals, and manufactured food throughout the whole plant.
 Green stems produce food through photosynthesis.

 Internal Structures
Stems
 Xylem: Tissue responsible for carrying water and nutrients from the roots to the leaves. It is located near the center of the stem.
 Xylem Up!!

 Internal Structure:
Stems
 Phloem: Tissue responsible for carrying food produced in the leaf to the rest of the plant. The phloem is usually located near the outside of the stem.
 Phloem Down!!

Stems
 Internal Structure
 Cambium: Tissue responsible for the production of new xylum and phloem. It is found between the xylum and phloem.

 Specialized Stems
Stems
 Bulbs: Short flattened stem which has several fleshy leaves. Bulbs are found beneath the soil.
 Example: Onions
 Corm: Sphyrical structure similar to a bulb.
 Example: Gladiolus

 Specialized Stems
Stems
 Rhizome: Thick underground stem which lies horizontally.

Example: Mother in Law’s Tongue
 Stolon: Horizontal stem which lies above the ground (often called runners).

Example: Strawberry runners

 Specialized Stems
Stems
 Tuber: Rhizome with a tip that is swollen with stored food.
 Example: Potatoes.

Leaves
 Functions:
 Produce food for the plants. They are designed to efficiently collect light and use that light to make energy.

Leaves
 Leaf Parts
 Leaf Blade: Large, broad, flat surface whose job is to collect sunlight
 Petiole: supports the leaf and holds it away from the stem.
 Midrib: Main vein running down the center of the leaf. It helps hold the leaf so it is facing the sun.

Leaves
 Leaf Types
 Simple leaf: Has only one leaf on the petiole.
 Compound leaf: A leaf with multiple blades.

Leaves
 Vein Patterns
 Parallel: Veins never cross. Found in monocots.
 Netted: Veins form a network. Found in Dicots.

Leaves
 Leaf Layers:
 Cuticle: The top waxy, non-cellular part of the leaf. Its job is to prevent water escaping.
 Epidermis: Skin like layer of cells found on both the top and bottom of the leaf. Its job is to protect the leaf.

Leaves
 Leaf Layers
 Palisade Mesophyll: A layer of cells standing on end directly below the upper epidermis. This area is responsible for photosynthesis.
 Spongy Mesophyll: Loosely packed cells located beneath the palasade mesophyll. This area is responsible for holding the products of photosynthesis.

Leaves
 Leaf Layers
 Stomata: Holes in the lower epidermis responisble for gas exchange.

Guard Cells: Surround the stomata’s which open and close them.

Leaf Layers

Photosynthesis
 Photosynthesis: A chemical process by which a plant turns light energy from the sun into chemical energy in the form of sugar.

Photosynthesis
 Photosynthesis
 The plant uses water and carbon dioxide to produce glucose (a sugar). The by product of photosynthesis is oxygen.
 These chemical reactions take place inside the cells near the chloroplasts. Chloroplasts are filled with
Chlorphyll which makes the plants green.

Photosynthesis
 Photosynthesis

Plants don’t photosynthesize. Chloroplasts do!
Plants just happen to be lucky enough to have chloroplasts in their cells.

Respiration
 Cellular Respiration: The opposite of photosynthesis. This process breaks sugars down so plants can use them.
 Similar to digestion in animals.
 Takes place in a place in the cell called the mitochondria.

Respiration
 How are photosynthesis and respiration important to us as human beings?

Flowers
 Flower Parts -- Male
 Stamen: Male part of the flower.
 Filament: Stalk like in the stamen that holds up the anther
 Anther: Sack-like structure that contains pollen.

Flowers
 Flower Parts -- Male
 Pollen grains are released from the anther that contains sperm.
 Staminate: Flowers that have only male parts.

Flowers
 Flower Parts – Female
 Pistil: Female part of the flower
 Stigma: Sticky part of the pistil that is receptive to pollen.
 Style: Rod shaped middle part that has a swollen base (ovary) containing eggs

Flowers
 Flower Parts – Neither male or female
 Petals: colorful leaf-like structures which attract animals and insects.
 Corolla: When all of the petals are fused together.
 Sepals: Green leaves that protect the flower before it opens.

Flowers
 Flower Parts – Niether male or female
 Calyx: When all of the sepals are fused together.

Flowers
 Sexual Reproduction in Plants: Two parents
(meiosis)
 #1 The stamen releases pollen.
 #2 Pollen is carried by wind, gravity, animals, or insects to the stigma of another flower. (This is when pollination occurs)
 #3 The pollen moves from the stigma down through in a pollen tube the style depositing sperm in the ovary.

Flowers
 Sexual Reproduction in Plants:
 #4 When the sperm has been deposited in the ovary fertilization has occurred.
 #5 When the eggs have been fertilized, the ovary and surrounding tissue start to enlarge to become a fruit and the fertilized eggs become seeds.

Flowers
 Flower Types:
 Perfect Flower: Has both male and female parts.
 Imperfect Flower: A flower that is missing either male or female parts.
 Complete Flower: Flowers that have sepals, petals, pistils, and stamens.

Flowers
 Flower Types:
 Incomplete Flowers: When a flower is missing sepals, petals, pistils, or stamen.
 Imperfect Flowers are always incomplete.
Incomplete flowers may or may not be imperfect

Light
 Plants need the colors blue and red to activate chlorophyll.
 Light bulbs are deficient in the color blue.
 Fluorescent tubes are deficient in the color red.

Light
 Special grow lights are made that carry the correct blue and red wavelengths.
 Light intensity is measured in foot candles.
 Foot Candle: The amount of light given off by a candle a foot away.

Light
 Plants have adapted to survive in either high, partial, or low light intensities.

Light
 Photoperiod: The length of daylight.
 Short Day Plants: Plants that begin to flower when the nights are over 12 hours long.
 Long Day Plants: Begin to flower when the nights are under 12 hours long.
 Neutral Plants: Flowering response is unaffected by day length.

Temperature
 Hardiness: A plants ability to withstand cold temperatures.
 Hardiness is measured using the USDA hardiness Zone Map.
 We are in zone 5, Logan is in Zone 4

Temperature

Temperature
 Wilting: A condition caused by excess heat and dryness. When a plant wilts it closes its’ stomatas, and the cells loose their turgor pressure.

Air
 Oxygen: Is needed by the plant for respiration.
It is obtained by the roots.
 Carbon Dioxide: Is needed by the plant for photosynthesis. It is obtained through the stomata’s

Water
 Plants get most of the water through their roots. Some small quantities are also obtained through the stems.
 Difficult task about watering: Plants need both adequete levels of water and oxygen.

Water
 Plants should be watered all the way through the root zone to encourage even root growth.
 Plants should be grown in pots with drainage holes so the water can drain and allow oxygen into the root zone.

Growth Regulators
 Plant hormones: growth regulators naturally produced by the plant.
 Auxins: Growth hormones produced by the apical meristem. They encourage height growth, and discourage lateral growth.

Growth Regulators
 Plant Hormones:
 Cytokinins: Produced in roots and seeds, and are responsible for cell division and differentiation.
 Ethylene: Produced by ripening fruit, it stimulates flowering, and ripening.

Growth Regulators
 Plant Hormones:
 Gibberellins: Produced in stems, roots, and young leaves. They are responsible for internodal elongation.
 Abscisic Acid: Found in seeds. A hormone which inhibits growth.

Ethylene
The effect of Auxins
Giberrellins Effect on dwarf bean plants

Growth Regulators
 Commercial Uses:
 A-rest, B-Nine, Cycocel, Florel: Used on poinsettias, Easter Lilies, and Chrysanthemums to reduce size to make a shorter bushier, and more attractive plant.
 Rootone and Hormodin: Used to help plants root more quickly.

Growth Regulators
 Commercial Uses:
 Ethylene gas: Used to ripen bananas when they get to market. Used to induce flowering in pineapple crops.

Plant Classification
 Non Flowering
 Ferns
 Cone-Producers (Conifers)
 Flowering
 Monocots
 Dicots

 Leaves have parallel Veins


Fibrous Roots
Flower parts in 3’s
 Seed has one part (cotyledon)
 Vascular bundles are scattered

 Leaves have branched Veins


Tap Roots
Flower parts in 4’s & 5’s
 Seed has two parts (cotyledons)
 Vascular bundles are in a ring